This application claims priority from Japanese Patent Application No. 2002-134691 filed May 9, 2002, which is incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to a cable connector for electrically connecting one end of a cable to a circuit board.
2. Description of the Related Art
When electric components are electrically connected to each other in the interior of an electronic apparatus, a cable connector is in practical use. The cable connector electrically connects electrical components to a printed circuit board via a flexible flat cable (FFC) or a flexible printed circuit (FPC). As the cable connector, for example, a rotary type or a slide type which is different from each other in the manner of fixation of the cable is in practical use. As shown in FIGS. 21A and 21B, the cable connector of the rotary type includes, for example, a connector body 4 having a cable accommodation portion 12 disposed on a printed circuit board 2, a plurality of contact terminals 10ai (i=1 to n wherein n is a positive integer) for electrically connecting an electrode section of the printed circuit board 2 with a terminal section 6E of a flexible printed circuit 6, and a stopper member 8 supported in a rotational movably manner relative to the connector body 4, for carrying out the detachment and attachment of the terminal section of the flexible printed circuit 6 relative to the contact portion of the contact terminals 10ai. 
The connector body 4 has at one end thereof an inserting opening 14 through which the terminal section of the flexible printed circuit 6 connected to the connector body 4 passes. The inserting opening 14 communicates with the cable accommodation portion 12 formed in the interior of the connector body 4. The cable accommodation portion 12 is defined by being encircled with an inner wall of the connector body 4. A bottom opposed to the printed circuit board 2 in the cable accommodation portion 12 is opened. In a portion of the connector body 4 forming an upper part of the cable accommodation portion 12, opposite side ends of a proximal end portion of the stopper member 8 are respectively supported in a rotational movably manner. The stopper member 8 has a pressing surface 8a in a portion opposed to the cable accommodation portion 12, which touches to a back panel section 6B of the flexible printed circuit 6 described later and pressing the same toward the contact section of the contact terminals 10ai. 
The plurality of contact terminals 10ai are arranged in the cable accommodation portion 12 in correspondence to the array of the terminal section 6E of the flexible printed circuit 6. The respective contact terminal 10ai is comprised of a stationary terminal section 10S soldered to the terminal section of the printed circuit board 2, a bifurcated stopper section 10B and movable terminal section 10A, and a coupled section 10C for coupling a confluence portion of the stopper section 10B and the movable terminal section 10A with the stationary terminal section 10S.
A front end of the stopper portion 10B of the respective contact terminal 10ai is located to face a recess of the stopper member 8. Thereby, as shown in FIG. 21A, when a front end of the stopper member 8 is away from the cable accommodation portion 12; that is, when the stopper member 8 is in an unlocked state, the front end of the stopper 10B is engageable with the peripheral edge of the recess of the stopper member 8 to restrict an opening angle of the stopper member 8.
The movable terminal section 10A has a contact portion at a front end thereof for the electrical connection with the terminal section 6E of the flexible printed circuit 6.
The coupled section 10C is fixed to the connector body 4 by press-fitting a projection thereof into a slit formed adjacent to the cable accommodation portion 12 of the connector body 4.
According to such a structure, when the terminal section 6E of the flexible printed circuit 6 is electrically connected to the contact portion of the respective contact terminal 10ai, as shown in FIG. 21A, after the terminal section 6E of the flexible printed circuit 6 is inserted in the direction shown by an arrow F into the inserting opening 14 to a position in the vicinity of a back wall 4a defining a rear side of the cable accommodation portion 12, the front end of the stopper member 8 is made to rotationally move in the direction shown by an arrow L. Thus, the terminal section 6E of the flexible printed circuit 6 is pressed onto the contact portion of the movable terminal section 10A of the contact terminal 10ai by the pressing surface 8a of the stopper member 8 and electrically connected thereto. At that time, the terminal section 6E of the flexible printed circuit 6 is nipped by the pressing surface 8a of the stopper member 8 and the movable terminal section 10A of the respective contact terminal 10ai which carried out elastic displacement.
As shown in FIGS. 22A and 22B, the sliding type cable connector includes, for example, a connector body 18 having a cable accommodation portion 16 disposed on a printed circuit board 2, a plurality of contact terminals 20ai (i=1 to n wherein n is a positive integer) for electrically connecting an electrode section of the printed circuit board 2 with a terminal section 6E of a flexible printed circuit 6, and a stopper member 22 supported in a slidable manner relative to the connector body 18, for carrying out the detachment and attachment of the terminal section 6E of the flexible printed circuit 6 relative to the contact portion of the contact terminals 20ai. 
The connector body 18 has at one end thereof an inserting opening 24 through which the terminal section 6E of the flexible printed circuit 6 connected to the connector body 18 passes. The inserting opening 24 communicates with the cable accommodation portion 16 formed in the interior of the connector body 18. The cable accommodation portion 16 of the connector body 18 is defined by being encircled with an inner wall of the connector body 18. A guide groove 18g for supporting opposite ends of the stopper member 22 in a slidable manner is formed on the inside of the connector body 18 in which an upper part of the cable accommodation portion 16 is formed in the attachment/detachment direction of the flexible printed circuit 6. The stopper member 22 has, in a portion opposed to the cable accommodation portion 16, a pressing surface 22a for pressing a back panel 6B of the flexible printed circuit 6 toward the contact section of the contact terminal 20ai described later, while sliding the back panel 6B along a back panel 6B of the flexible printed circuit 6.
A guiding surface 22b having a slant portion 22s at the midpoint thereof is formed in a portion opposite to the pressing surface 22a of the stopper member 22.
The plurality of contact terminals 20ai are arranged in the cable accommodation portion 16 in correspondence to the array of the terminal section 6E of the flexible printed circuit 6. The respective contact terminal 20ai is comprised of a stationary terminal section 20S soldered to the terminal section of the printed circuit board 2, a bifurcated guiding piece 20B and movable terminal section 20A, and a coupled section 20C for coupling a confluence portion of the guiding piece 20B and the movable terminal section 20A with the stationary terminal section 20S.
A front end of the guiding piece 20B of the respective contact terminal 20ai is disposed to face the guiding surface 22b of the stopper member 22. The movable terminal section 20A has, at a front end thereof, a contact section for the electrical connection with the terminal section 6E of the flexible printed circuit 6.
The coupled section 20C is fixed to the connector body 18 by press-fitting a projection thereof into a slit formed adjacent to the cable accommodation portion 16 of the connector body 18.
Thus, as shown in FIG. 22A, when the slant portion 22s of the stopper member 22 is away from the cable accommodation portion 16; that is, in the unlocked state, the slant portion 22s of the stopper member 22 is away from the guiding piece 20B to be in the disengaged state. Accordingly, the terminal section 6E of the flexible printed circuit 6 can be inserted into the cable accommodation portion 16 through the inserting opening 24.
In this structure, upon the occasion of the electrical connection between the terminal section 6E of the flexible printed circuit 6 and the contact section of the respective contact terminal 20ai, when the slant portion 22s of the stopper member 22 is away from the cable accommodation portion 16 as shown in FIG. 22A, the terminal section 6E of the flexible printed circuit 6 is inserted through the inserting opening 24 in the direction shown by an arrow F to a position in the vicinity of the rear wall 18a defining a rear side of the cable accommodation portion 16, after which a front end of the stopper member 22 is made to slide in the direction shown by an arrow L. Accordingly, the terminal section 6E of the flexible printed circuit 6 is pressed onto the contact section of the movable terminal section 20A of the contact terminal 20ai by means of the pressing surface 22a of the stopper member 22 to establish the electrical connection.
At that time, the terminal section 6E of the flexible printed circuit 6 is nipped between the pressing surface 22a of the stopper member 22 and the movable terminal section 20A of the elastically deformed each contact terminal 20ai. 
In the above-mentioned rotary type or sliding type cable connector, immediately before the terminal section 6E of the flexible printed circuit 6 is held to the movable terminal section of the respective contact terminal 10ai or 20ai, the terminal section 6E is made to move from a position shown by a chain double-dashed line to another position shown by a solid line in FIG. 21A or 22A due to the mutual frictional force. Accordingly, there might be a risk in that the electrical connection becomes unreliable between the terminal section 6E and the contact section of the movable terminal section in the respective contact terminal 10ai or 20ai, or it is required to hold other end of the flexible printed circuit 6 so that an end face of the flexible printed circuit 6 does not collide with the rear wall 4a or 18a or it is needed to operate the stopper member 8 or 22 with the end face of the flexible printed circuit 6 touched.
Also, it is difficult to determine whether or not the terminal section 6E is assuredly connected with the contact portion of the movable terminal section of the respective contact terminal by the operation of the stopper member 8 and 22.
Furthermore, when any load exceeding a predetermined level is applied to the other end of the flexible printed circuit 6 in the direction opposite to the direction shown by an arrow F in FIGS. 21A and 22A, there might be a risk in that the stopper member 8 or 22 is made to rotationally move or slide to result in the unreliable electrical connection between the terminal section 6E of the flexible printed circuit 6.
In view of the above-mentioned problems, an object of the present invention is to provide a cable connector for electrically connecting one end of a cable to a circuit board, capable of assuredly and easily carrying out the attachment/detachment of the cable as well as avoiding the unreliable electrical connection even if an undesirable load is applied to the cable.
To achieve the above object, a cable connector according to the present invention comprises a cable accommodation portion having contact terminals to be electrically connected to a terminal section provided at one end of a cable together with a portion being engaged; the cable accommodation portion being capable of relative positioning the one end of the cable relative to the contact terminals and accommodating the one end of the cable therein; and a stopper member disposed in the cable accommodation portion to be movable in the thickness direction of the cable to be connected, having an opening for allowing one end of the cable to pass through the opening, an engaging portion to be selectively engageable with an end face of the portion being engaged of the cable inserted into the cable accommodation portion at edge of the opening.
Also, the cable connector may further comprise a biasing member for biasing the stopper member to maintain the engagement of the engaging section of the stopper member with the end surface of the portion being engaged of the cable when the one end of the cable is positioned relative to the contact terminals, and a restricting member for restricting an amount of movement of the stopper member caused by the biasing force of the biasing member.
The biasing member may be a leaf spring which is supported at one end by the stopper member and at the other end by the periphery of the cable accommodation portion.
The cable may be a flexible printed circuit.
The portion being engaged of the cable may be a step formed in a back panel.
A lock/unlock mechanism for carrying out the selective connection of the terminal section of the cable with the contact terminals of the cable accommodation portion may be constituted by the portion being engaged provided at the one end of the cable, the stopper member and the biasing member.
As apparent from the above description, according to the cable connector of the present, by providing the stopper member accommodated in the cable accommodation portion to be movable in the thickness direction of the cable to be connected; the stopper member having an opening for allowing one end of the cable to pass through the same and being provided at the periphery of the opening with the engaging section to be selectively engageable with an end face of the step of the cable inserted into the cable accommodation portion; the engaging section of the stopper member is movable in the thickness direction of the cable and engageable with the end face of the portion being engaged of the cable. Thus, it is possible to assuredly and easily carry out the attachment/detachment of the cable, whereby the unreliable electric connection is avoidable even though an undesirable load is applied to the cable.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings.